


As vast as the sea, dark as deep waters

by lawismyname



Category: Shingeki no Kyojin | Attack on Titan
Genre: Alternate Universe, Alternate Universe - Reincarnation, Armin's a dog, Biting, Blood Drinking, Bottom Eren Yeager, Claiming, Claiming Marks, Dark, Dominant Levi, Eren does not, Eren is very young, Eren's the oldest, F/M, IDK just be prepared coz Eren lost his memories and he and Levi do the frickle-frackle, Knotting, Levi has his past memories, M/M, Magic, Memory Loss, Mermaid Sex, Mermaid/Merman, Obsessed Levi, Possessive Levi, Pregnancy, So be warned, Submissive Eren Yeager, Top Levi, Yandere? Probably IDK, Ymir Isabel and Eren are siblings, fake death???, like seriously, my tags are stupid
Language: English
Status: Completed
Published: 2018-04-24
Updated: 2018-04-24
Packaged: 2019-04-27 03:19:32
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 9,980
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14416548
Author URL: https://archiveofourown.org/users/lawismyname/pseuds/lawismyname
Summary: And so here is another dark Riren fic for you guys, hahaha. I really couldn't help, and this fic is unbeta'ed because by beta got into the hospital so please excuse the mistakes.Rhiannon-san!! Please get well soon!!!!Beware of the tags.Anyway I hope ya'll enjoy this crap.





	As vast as the sea, dark as deep waters

**Author's Note:**

> And so here is another dark Riren fic for you guys, hahaha. I really couldn't help, and this fic is unbeta'ed because by beta got into the hospital so please excuse the mistakes.  
> Rhiannon-san!! Please get well soon!!!!  
> Beware of the tags.  
> Anyway I hope ya'll enjoy this crap.

The unfathomable darkness drifted into blinding light as a set of wide eyes squinted at the fading rays of the setting sun. Eren sat up, cringing at the heaviness that dragged his body into sluggishness. Long curled lashes flitted as he waited for his sight to adjust, the blurs and whirls of dizziness diminishing and when it did, he was greeted by the magnificent sight of the ocean at sunset. The little child was enthralled, the dips of the wavering sun painted the waters like a broken reflection – a shifting canvas that would soon transcend to darkness, the constellation and galaxies unfolding to welcome a moonless night.

His voice croaked harshly when called for his parents and his younger siblings. Eren wanted them to see such fascinating scenery, but a long minute had passed and he received no response. He turned, only to see that he was alone. There was no one but him at the beach. Or rather to say he was alone in the seemingly secluded island.

The feeling of wonderment instantly resided into fear. Panic and distress churned inside his stomach and they dripped to grapple his lungs like a boa constrictor, making him unable to properly breathe. Big fat tears poured from his brilliant eyes, clouding the once beautiful scenery into distorted images. He pondered himself for an explanation, a reason of why he was alone. Did he lose himself while he was wandering off and fell asleep as tiredness overcame him. Or could his parents have forgotten about him?

No no no no. The 12 year old cried. His parents love him knew that, or could it be the whispers of I love yous before he went to bed were just petty lies and his parents got tired of taking care of him.

He shook his head angrily.  He refused to believe his parents would abandon him. He pondered hard until he felt a flash of pain in the side of his head, his mind recollecting bits of events this morning. They went island hoping, Eren with his parents, Isabel and baby Ymir, together with some staff of the cruise, and... He can't remember. Only the cerulean abyss welcoming him into its depths.

"Oh, you're finally awake," the voice pulled him back to reality. He looked up to see piercing gray eyes with an unfamiliar look in his eyes. His heart immediately jumped at the thought of being safe, that the person, a stranger he might be, would be able to help him back to his parents. 

"Sir p-please help me. I-I have to get back please. Can you bring me back to my parents?" He beseeched but the man only gave him a saddened look. He inched closer to him, and offered a vial with crimson fluid.

"Drink this. It will aid you to heal faster." Eren frowned in confusion. Heal? What does he mean? Eren made a once over his body, finding no blood dripping from him. He heard the other man sigh and he once again turn back to the other.

"You don't remember do you?" The stranger stated the words rather than question. Eren shook his head.

"There was a storm Eren. You were overthrown from the yacht and I saved you." He explained and as if triggered by the man's words a sharp pang of pain thrummed through his left temple. The young brunet winced, his youthful features morphing as his mind played back the events in a horrifyingly vivid scene.

_His mother's voice echoed in his ear along with his father. The yacht was teetering dangerously on the water. The waves were relentless and harsh, searching to seize and swallow them to the foreign dark waters._

_He felt it slam over him, his body being carried away. There was a breathless punch on his left chest, and he screamed out of hurt. There's a fleeting moment of falling, then a stinging plunge as he was engulfed into the vehement sea._

_He couldn't breathe; there was no air but salty waters to invade his chest and drown his lungs. He struggled, his limbs flailing to bring him up high into the surface but it was the opposite. He was sinking into the deeper and darker parts of the ocean._

Shaking hands moved in haste as they lift the damp shirt. A gasp slipped from his lips and his eyes widened as he took in the morbidly large discoloration on his chest. Trepidation enclosed his throat and it coaxed the lightheadedness to return. The thought of the injury brought forth a paralyzing numbness to reside stronger, momentarily distracting him instead of the stinging pain that washed over his body.

He began to panic as he was beginning to breathe rapidly, his heart racing with his sudden forceful intake of air. His thoughts were drowning in desperation and anxiety and he cried as tears poured to his cheeks.

He was going to die. His family was gone and he was all alone, dying.

Something wet and cold caught his mouth and a strong grip snaking around his back. A gasp left his mouth, his surprise distracting him from his panic attack. The stranger was kissing him with lips moving about along his own. They suck his bottom lip gently before they trailed away to his forehead.

"There, now you've calm down." The man said, and Eren realized that he had stopped hyperventilating. "I'm sorry about your parents, but there was nothing I could do to save them. I had to get you to safety and when I came back to them – the ship had been wrecked." The man further explained. There was a tone of regret and sadness in his voice and it made Eren's heart clench. He doesn't want to believe the man but given the kind of storm, he knew the possibility that his parents had failed to survive.

"Drink this, it will help you to heal faster." The man handed him vial, and Eren looked at him, uncertain and suspicious.

"Don't worry, it's not poison. Wouldn’t trouble to save you if I wanted you gone." Having the man's point taken, he pulled off the cork and drank its content. It tasted sweet and Eren had downed it to the last drop. The sting of the bruise immediately faded, surprising the young child at its immediate effect. Eren offered though weakly, a small smile at the man in thanks but something at the corner of his eyes caught his attention.

His turquoise eyes widened as he gaped at the man's supposedly lower half. It was a fish's tail with a rich color of royal blue and violet, the fins a gentle rendition of blue-violet. It flexed as the man curled it closer to him, and was tempted to touch the beautifully sleek surface of the muscular tail. Now alerted with the peculiar limb, Eren's eyes fixated back to the man's features and noticed a few differences. His ears were pointed with a few glimmering scales of grey and blue on the sides of his cheeks that littered down to his neck where three folded lines implanted on each side. His fingers webbed with sharp claws looking pristine and smooth like a polished knife.

"You're a mermaid?" Eren whispered, enthralled at his discovery. "It's merman, Eren. But anyway, you should take your shirt off. You'll get sick if you keep on wearing wet clothes." A tilt of his head showed his confusion and weakly he asked, "How did you know my name? I don't remember telling it to you."

The older male gave him a raised brow and Eren noticed that he had dark silver eyes, piercing and intimidating as he lost himself in them. "The woman, she shouted your name when you fell. I'm Levi by the way, sorry if I forgot to introduce myself earlier. You've been unconscious for a few hours and I was too absorbed of my happiness of finally seeing you open your pretty eyes."

The brunet knew that it was his mother whom was Levi referring to, but despite the hurt in his chest, a blush crept on Eren's checks at the compliment and mumbled a shy 'nice to meet you'. Levi smirked at his meek reply and his tail straightened then shuddered before his scales faded into porcelain flesh. The young child had to look away in embarrassment as the man suddenly stood with human legs, bare in all its muscled glory.

"Now, let's get you fed and warm."

Fire crackled on the pit in its devour of the wooden fuel. Eren added a branch before checking the fishes if it was cooked. His clothes hung on the makeshift holder, and Eren edged closer to the warm flames for the comfort of heat.

Levi had left to the forest in search for any edible fruits and fresh water, though he wouldn't mind the sweet juice of coconuts as a daily source of refreshment. Eren craned his head up, watching the night sky in utter awe. The stars had taken its place like tiny jewels on the dark mantle, like glittering tears unfolding the mysteries of the worlds above the sky; the wind ghosted briefly against his exposed body and he shivered as goose bumps popped up on his skin.

He hadn't notice Levi had returned from his scout until a soft button up was thrown on his way. The man had seated himself beside him and Eren immediately noticed his skin clad with clothes. The question of its source must have shown on his face when the merman spoke," You'd be surprised how many clothes could get washed up in the sea. I gather them so I can use them on land. Here, I found some fruits and water, though I can say you enjoyed the coconuts better." There was a smile in his voice that Eren interpreted that the merman was teasing him, and so he decidedly slipped on the button up to hide the faint blush on his cheeks.

“Thank you.” He mumbled in gratitude. The fish had been cooked and Eren feasted on it, not realizing his famished need for food. But then he noticed that the man wasn't taking any meal, the young child stared unknowingly curious at the older man whom stared back at him with an amused smile. “A-aren’t you going to eat?” He asked, offering the fish and the merman shook his head.

“Don’t worry about me, I’m not hungry. I caught all these for you so no need to hold back.” Levi assured and Eren continued, consuming two out of three fishes and half of the fruits. Once full, the young brunet caught himself gazing out the sea, his chest tightening painfully with the tragic fate of his family.

Little and loud Isabel and baby Ymir. They were so young and they didn’t deserve the painful end. Eren loved them with all his heart and it broke him to know that he will never see them again.

Levi had tried to save them yet it had been too late. The sea which he loved so much snatched away his beloved family. Tears trailed from his eyes and Eren only noticed that Levi had moved closer to him as the soft heat emanating from the man wafted into his flesh. A comforting hand wrapped around him as if to shelter him, protect him from all the worries and pain that the world was causing him.

He let himself nuzzle on the man’s chest, sniffling loudly as he tried to halt his tears from pouring out. A soft hum vibrated through him, and a song filled his ears. A voice so magical and captivating sang a foreign lullaby and with its gentle tone and hypnotizing lull made the child curl into the man’s strong arms, its feelings dawned to him despite the mysterious lyrics.

_I am here Eren. I will never leave you. You are mine._

It was a declaration and the brunet was somehow relieved of hearing the unspoken promise. He had been terrified of being alone. Everyone was gone and he had nothing left except this stranger, this person that offered him solace and company that he so needed and for that Eren was thankful, contented and with a smile he fell into slumber, caged in Levi’s arms and warmth.

 

* * *

Levi had been searching for Eren, that much he knew the reason of his existence; to find his one true love and mate, his beloved Eren.

Levi remembered. The past, the tragedy that he and Eren had endured and succumbed into. Of blood, fire and flesh and a promise that he vowed on the cold lips of his lover. The sea had welcomed them at their end, and Levi given a second life, was born at the sea.

He learned the greatness and vast mysteries of the oceans, and he was bestowed the knowledge of magic. Both light and dark.

But fate had never been kinder to anyone, for he had lived for centuries but there was no sign of Eren. He traveled through the algid and unforgiving waters and crossed the torrential storms. He met others alike to him, but he kept looking for his true home, his beloved – his Eren - for once he found him, Levi knew that everything was all worth it.

Then in the warm waters of the shallow shores, he found hope.

A woman. Praying with fervor and desperation for a child that her barren womb could never bear fruit of. Her looks reminded him of his beloved, and he came to realize that in the past she was the woman whom brought his Eren to life. So with purpose and determination, Levi called unto her, whispered to her in a voice like the soft curling waves, beckoning her with a promise to fulfill any wish of her heart’s desire… nevertheless with a condition.

Levi swam close, careful yet certain as she looked the source of the lulling voice. Surprise filled her features upon settling her sight to the merman, but Levi was determined and so he reassured to the woman.

“Fear not, I am of no harm to you. But the cry of your prayers echoes through the waves, may I know the reason of your grief?” His voice curled with a strange accent. It had been long since he spoke and the world had changed developed a myriad of languages. Levi had studied and learnt them but he had found no use for them until now.

The woman’s eyes turned painful, and a tear dripped into the ocean as she choked, “It’s my body. I have trouble conceiving and the doctors concluded that I am barren for the rest of my life.”

His heart felt a sharp pang upon the spoken words despite having to hear them in the waters. Yet Levi refused to be faltered or desponded. He knew that he was going against fate as it seem planned to make Levi wait longer for his lover’s return, but he wasn’t one to sit still if an opportunity presented itself. Not when a solution was within reach and plausible by the knowledge accumulated from all the centuries of his search.

“Cry no more woman, I have a solution for your prayers, but it comes with a price.” He warned, though he knew if the brunette was desperate enough she would accept his proposition no matter what the consequences.

He swam swiftly to his lair to gather a vessel, and returned to Carla with a vial of red liquid; that of his blood which magic coursed and lived in it. He had incredible healing capabilities and if drank by any of the sick or injured, the body would transform itself to a much competent and healthier state. He also casted a spell on it to change its taste so the woman’s stomach won’t push the fluid out of her system as response to the taste of blood. Levi knew how repulsed would she be if she ever knew the true identity of its contents.

And she had been so elated with his offer, drank the vial without so much hesitance that she hadn’t asked the price for the solution of her problem. Levi stated the condition but she had been blindsided by happiness and joy, she mindlessly agreed. And the deal was struck, and Levi would wait until Eren would turn 16 so he would be with him.

Levi never failed to swim over to the steeping docks where Carla often visits so early and shortly after dawn and near twilight. The woman had changed drastically over the days, her body more robust and energetic with an endless smile on her lips. She had relayed the news to the merman, and Levi rejoiced, his heart beating wildly at the fact that she was conceiving.

A few days had passed, and Carla brought her husband to be introduced to him. The man was intrigued by him, his eyes full of inquisition yet nevertheless when he spoke, his voice was filled of gratitude towards the merman. Levi found out that they were married for 6 years and have been trying to have a child and failed so many times until Levi offered his help.

He was straightforward with his suspicions towards the merman but Levi decided that he posed no threat to his plans as the man offered his wife to reside near the ocean. He was a doctor and not only that a multimillionaire company owner of the renowned pharmaceutical manufacturing industry. He was in debt with the merman, and so to lessen his wife’s task of visiting the boating docks, he specifically brought the nearest house to the ocean and had a private dock made with a shelter so Carla could stay long even in midday to converse with the merman.

Day by day, Eren started to grow, and when he was born on the same day from his past life, Levi had been high above the heavens. It was like freedom, and hope was at his grasps, so tangible and precious, close to his hands as Carla, brought him to be introduced for the first time.

“His name’s Eren. Isn’t he wonderful?” Carla crooned, caressing the soft plump of the baby’s delicate cheeks. Levi only nodded in silence, his eyes stinging as he tried to hold back his tears. He hadn’t cried for centuries, and it felt foreign, yet it was because of his Eren and Levi decided that he doesn’t mind shedding a tear for his beloved.

“Eren.” He said in a reverent whisper.

He was enchanting, so fragile and curious as he leaned his head towards Levi upon hearing his voice. A rare smile graced the merman’s lips, and reached up, careful and gently to touch the flailing hands that seemed to be reaching towards him. He had to fight the urge to take the baby and drag him to the ocean—his home, but he had a deal and Levi wasn’t one to go back on his word.

He’d have to wait; only a few more years and they would be together as it was from the past.

“ _The ocean is in you, love. The call of the waves and the song of the depths will always be with you, reaching and beckoning. You are mine as I am yours, forever and an eternity.”_ His voice rang like a lyrical song, his foreign tongue speaking the vow he so long wanted to say, and the child made a toothless smile, so pure and full of joy. And Levi knew that Eren had taken his words as his, though he won’t remember them, its essence had sank into his soul, and with a final whisper, Levi casted his charm, a mark to which would bond and connect the two.

Carla, oblivious to the meanings of his words, giggled in her assumptions that the merman was attempting to communicate with the child, but seemed to have trouble conversing so with his own excitement.

They left near twilight, and Levi dove back to the ocean, searching its depths a worthy gift for his beloved. There were hidden jewels at the dark recesses of the ocean, the sunken ships that sank long before time, encasing so many treasures and Levi having to find the most beautiful turquoise bracelet that was surrounded with royal blue sapphires, he knew that it was the one that Eren would love to wear around his hand. And his necklace one that he’d kept for so long, his only remaining memory from their past, of their love and their promise.

Whether Eren would remember him or not, he was still his Eren. The past doesn’t matter after all, only them and the time they had now for a second chance to be together. He’ll give them as wedding gifts, surely Eren would be delighted. He’d always been so appreciative of little things having so little of such luxury behind the walls. The smallest gestures and presents were enough to make Eren’s heart swell and smile widely in happiness and gratitude.

Carla visited the docks few weeks after. Levi understood the frail conditions of both mother and child, though his blood healed Carla, its magic and ability had been used up with the pregnancy in its assurance of a healthy and successful birth, besides it must have been a tiring task to care for such a babe like Eren, always so energetic and full of life.

The young brunet had grown plump and robust; his curtailed lids now open to reveal his jewel-like eyes. Eren was vigorous, restless like a toddler of endless curiosity, and the merman was amused. Such behavior was innate to his beloved, remembering his exuberance and stern determination. Both were a welcoming sight and a source of his worries. Eren had been working too hard, always exerting his body to fatigue, in training and expeditions, and fighting to the point where blood and flesh had been exchanged for a small width of triumph against the enemy of mankind.

Eren was making incoherent mumbles and squirmed in his mother’s arms. Levi gave a chuckle when he squealed upon noticing the stranger. He tried leaning in and grabbed the merman’s peculiar ears, but failed as Carla chided at him with a hand over the outstretched ones. She apologized to the merman for the child’s untamed inquisitiveness. But Levi shook his head, amused by the child’s positive reaction towards him and so he reached out a wet hand to which the child immediately took ahold after managing to slip his little limbs from his mother’s grasps. The child elicited a pitched squeal and pulled the hand to his mouth and sucked on the salty skin as if it were sweet a treat – though Levi knew, it might have been an effect of his blood. After all Eren was blessed of the sea, and salt water won’t taste as distasteful on its precious little mouth.

The gesture though simple and innocent, it brought a blazing fire to the merman’s loins. Eren had always managed to incite his desires and coax his primal nature, but he kept his face placated with a mask of neutrality, and tutted as he gently unclasped the fragile and soft hands off his. “Eren.” He spoke and the child wiggled excitedly at the sound of his voice and responded to his call as he tilted his head cutely. _Heh, cute._ The merman mused and gave a glimpse of a smile.

“He looks wonderful Carla and very curious, I see.” He said, and the woman nodded and gave her son a kiss on the cheek, earning an excited cry from Eren.

“He is and truth to be told, he’s a hurricane of endless energy. Grisha and I are always exhausted every day, but it’s not bad, Eren had his angelic times, don’t you my little _engel._ ”

Levi nodded, understanding the situation. Though Eren would likely grow and control his curiosity, his obedience and loyalty was a force to be reckoned with. He never complained Levi’s commands and wishes but it might be because Eren wanted to please him due to his unparalled admiration to the previous corporal.

A pale palm waved with a hypnotic stroke, skimming the surface of the water. A bubble of water rose as the merman lifted his hand and the child didn’t held back a surprised yet excited screech. The layer was thin, fragile and breakable with the sun’s rays glimmering and dancing as it passed through the medium. Eren tried to capture it but it broke into a million microscopic glittering droplets upon the slightest contact of his tiny fingers. Chocolate brows furrowed in confusion and sadness, the golden skin of his face flaring red as a wail gurgled up in his throat. Levi had been alarmed, not wanting to see a tear on his lover’s gem like eyes and so he made quickly made a few more water bubbles, even manipulated the water to dance and take form to a seahorse.

Eren’s face immediately lightened up and he jumped happily on his mother’s arms, Carla laughing as she shook his head to her son’s rambunctious vibe.

“Levi, you spoil him too much.” The mother mentioned, and Levi watched as Eren played (attempted to as per his restrained position), his teal eyes illuminating like the purest tropical sea waters.

“It’s fine.” _It’s for Eren after all._ His mind offered silently.

The morning sun arose and the comforting heat of the sun burned to a furnace. Eren and Carla had to leave since Eren was feeling tired and sleepy with playing, and Levi swam back to the ocean to rest and hunt for food. He had contemplated walking on land and try to visit Eren but that may cause drawbacks to the plan. Carla might start to get frightened of him and see him as a threat especially with their limited time with Eren. Having the power and ability shift his tail to a pair of legs and to walk and scourge the land might start to trigger fear and worry to the woman about the merman's capabilities. Also not to mention his powers lessen whenever he was away from the sea. The waters are the source of his energy, and his nature has eternally interconnected with ocean, and so he settled with the pretense of only being able to remain in the sea, hiding away his superior presentation as the strongest wielder and creature of the waves.

Days shifted to weeks and months turned to a year. Eren had grown and learnt, attaining motor skills and miniscule comprehension with words. He was walking, stumbling, steps short yet certain as his feet scurried to the thick wooden docks. A guiding hand held onto him, his mother’s voice whispering encouragement and praises as he reached to the edge where a man, half submerged on the water, was waiting for him with a light of joy in his eyes.

Eren grumbled, voice high with excitement. “Wev-ai! Wev-ai!” He called out, reaching his free hand to the cold, wet face of the merman’s. Carla made a soft chuckle, chastising the toddler when he tried to pull the elongated ears. Eren seemed to find them fascinating, his curiosity just demanding to be quenched as his dull fingers scratched the glistening scales trailing on his temples.  “How are you little jewel? Did you enjoy yesterday’s celebration?” Levi asked, his voice taking a melodic tone as he poked the child’s side, earning a burst of giggles from the brunet. “Bet you did little rascal. Ate a plateful of cake didn’t you?!” It was just the day before that Eren had his 1st birthday. Carla and Grisha planned a party, one that sadly Levi couldn’t attend to, but that did not mean that he was clueless of the event. He’d used his magic to watch over his beloved, and despite having to miss the day without his Eren, the joyful smile and ever flowing laughter of the young brunet was enough to fill the loneliness and wash away the heavy feeling of frustration.

“Caake!! Choclate! Wev-ai!!” Eren squealed, clapping his hands upon remembering the saccharine treat.

“He sure did. Made a mess with the other kids, but he pretty much enjoyed yesterday’s celebration. He absolutely loved the dolphin stuff toy his uncle Marco gifted to him, he didn’t want to let it go, he even slept with it.”

“Min!! Arrmin!! “ Eren chanted, “Mama! Armin doggy!”

“Yes, Grisha gave him a dog, a golden retriever. The little puppy was already in love with him, sticks around wherever he goes.” Carla continued, brushing her son’s silky locks out of his eyes. Levi nodded, listening quietly despite having to know. It would be creepy for the mother to discover that a merman was spying over the enchanted pools of his cave, his eyes peering over the innocent child all day and night.

“There was also a newly opened zoo that Grisha would like bring Eren to, though he thought of waiting for a few months until he grows up a bit.”

It seemed like Eren was generously spoiled, and somehow it irked Levi that wasn’t doing the same. He wished he could do the same, even more to his beloved mate. But Levi let fact that a few years later he would be able to do so, even for a thousand years.  

He pulled his gift to the youngling out of the water surface, placing an intricately made music box on the edge of the dock. Levi managed to make use of the antiquated materials, flourishing it with jewels and pearls of various colors. Using his magic, he formed a song to his lover, a soft lullaby to lavish his dreams with sweetness and love and no nightmare shall ever scar his Eren’s thoughts.

Eren opened the chest, and his jewels eyes curtailed slowly to slumber as he was lulled to a dreamscape of the most saccharine kind. Carla awed, and cooed the sleepy child, her eyes glowing with maternal love and happiness.

“It seemed like we finally have something to make him fall asleep on time.” She chirped, maneuvering the babe in her arms as Eren’s eyes closed shut. There was gentle and contented smile on his strawberry lips that made the merman’s heart clench in appreciation. His lover deserved only happiness and security and he would give everything just to ensure that.

“Thank you Levi. That is very nice of you to present him such a wonderful gift. You’ve done so much for my little one, and I couldn’t thank you enough.” The woman spoke, and Levi answered with a nod and a smile.

“It seemed like I have to bring him home earlier than intended. Sorry, you must’ve been wanting to play with him since you couldn’t yesterday.”

“It’s ok. I don’t mind. Take him home, Carla. Goodnight.” The merman bid his goodbye and swam back to his homely cavern, changing to his human form as he travelled deep into its recesses for its crystal pools. There he chanted a spell and watched as Eren’s dreams unfolded on the crystalline surface.

It revealed Eren, in his arms as they flew in the sky with their own set of white wings.

The next visits were coming to be less frequent that the previous. Carla excused that Eren was brought to the hospital for his shots and checkups, but as the days proceeded to months, the visits became less until it suddenly came to a stop.

Levi waited, never failing to return to the surface in hopes that his Eren was to be brought to him. But when five full months had passed, his patience wore thin and so the merman decided to journey the land.

He came to the Yeager’s residence. Knocked multiple of times, and when no one answered he broke the wooden door, surprised of the isolated state of the house. He scourged every room of the building, breaking and hurling furniture that tended to get in his way. He reached to Eren’s room, his hands immediately curling around the small music box that lay haphazardly on the floor.

Tears were hot and steaming red as it trailed on his face, his eyes glowing crimson with contempt and betrayal. His tongue tasted bitter, the poisonous vengeance in his mouth overflowing with rage. The grim realization pierced his chest, and a thousand times it hammered into his heart.

The family had left without telling him, dragging Eren away from him. Fury burned like a ferocious wild fire, and Levi cursed, hating and vowing to take back what belonged to him. Carla and Grisha were stupid to think that they could take Eren from him. He will hunt them down, and he will make them suffer the pain of losing a child.

The ocean was restless that night, the waves unforgiving as the merman shouted Eren’s name into the thunderous sky.

Grisha had brought them to another country. That he knew when his clairvoyance pool showed as Levi watched critically. The link between he and Eren was thin, almost as if barely straining to hold on. The man was wise enough to keep them away from the ocean but after years, the man had come to delude himself to have successfully escaped the merman, he let Eren visit the salty waters of the sea. Levi knew the waters too well, and with his willful and powerful tail, he swam across the world. The bond between him and Eren served as his compass, the power of the ocean directing him, weaving stronger waves into the bond as Eren was amidst the waters of the sea.

He called the wind and summoned the clouds, the waters of the sea curling with his command as he brought forth a powerful storm to crash and bellow at the ship. With and greed and long, he swept Eren off, the torrential sea enveloping his lover in its cold embrace so Levi could adjoin and hold his lover after for so long of craving.

And now his strong arms cradled the sound body that curled in repose. Levi had finally succeeded. Damn him to hell if he would ever allow Eren to be taken away from him ever again.

The days passed into a fantastical dream. Eren was starting to reveal himself more, his trust fully entrusted to the merman and Levi was high every single moment they both shared.

Though Eren would sometimes relapse to a rueful state, the memories of his family brandishing his joyful thoughts and Eren would weep in his arms, the names of his parents weaving through quivering red lips. It hurt Levi to see Eren cry, especially if the reason of his tears were the people that tried to steal his beloved away from him. So Levi has come to a decision to erase Eren’s memories. He doesn't need his past memories of his childhood and of his human family if it only caused him sadness and sorrow. Granted that Isabel had been born as Eren's sister, Levi was content that Isabel was alive and well.

After all, what he told Eren, about his parents perishing from the storm was a lie. For how could they suffer the loss of their eldest son if they sunk into the depths of the ocean, cold and slowly decomposing to feed the littlest of fishes, their bones serving as home to some. Not to mention, he owe Isabel her second life and though he felt a smidge of guilt in hurting her by the loss of her older brother, but his wrath towards Carla and Grisha’s betrayal and his own grief and longing for Eren for so many centuries had overcame his remorse.

So Levi gave him the sweetest fruit, one that would erase the memories of his human life before their meeting as the young child curled in his warmth as he slumbered flush to his beating chest.

Levi would be the only one he knew and the one Eren would only need. Once the moon passes and become full, Levi will turn him to a mermaid, the female counterpart of his kind. Levi will mate with him to establish a more stable and profound bond and Eren would be able to bear his children, and side by side they’ll live blissfully in the ocean.

 

The soft lull of the waves brought the pair of wide oceanic eyes to a shut. The night enshrouded the skies, the galaxies of the universe unveiling their wonder as the soft ripples of the ocean emanated their shine in its broken mirage and the light of the moon provided a soft illumination on the island where a human and merman resided for a sojourn while.

Eren breathed in the scent of salty waters, the full fragrance of forest and hot masculinity. Strong arms enveloped him in a reverent embrace, and the brunet nuzzled further to its fondness and heat, hearing lavished by the rick thickness of the merman’s voice as it sung his declaration of love to him.

His eyes only unfolded when the song came to an end, warm lips touching his as a  greeting and Eren smiled, shy yet elated by the look of adoration he was given. Levi had always directed him such a gaze and it will never fail to make the younger’s heart jump with pure happiness.

“Sing me some more, Levi.” The brunet asked, eyes sparkling with excitement as he edged closer to the merman, arms wrapped around Levi’s neck. A blushed decorated the darkened golden skin of his cheeks as he was flashed a smirk, a large and rough hand resting on the inside of his thigh.

“I spoil you too much and yet I could not resist you. Is this some charm I am not aware of? What have you done to my poor heart, my beloved angel.” Levi teased, kissing the lovely color of rose pink surfacing on Eren’s right earlobe thus eliciting a giggle from the younger male.

“That tickles! I do not know such magic but since I came from the heavens, don’t you think that it is inherent of me to own such charms to ensnare your heart, my merman?” There’s a playful lilt in the younger’s voice that made the older male smile in fond recognition, and Eren laid on the chiseled chest, the beating heart of the merman’s filling his ears with its soothing rhythm.

The merman had the urge to kiss those pretty pink lips as a rush of heat journeyed to his loins, such endearing display enticed so many lascivious imaginings and the merman could barely held on his restraints if Eren continues on with his adorable quirks and behavior.

Now that Levi had successfully erased the young child’s memories of his human life, he had successfully led the young child to believe that he was a survivor of a shipwreck, the impact of the hit on his head causing him to lose his memories. Now Levi was preparing Eren for his transformation, to be his eternal mate and with the lapse through the full moon ending, the merman couldn’t be more ecstatic. He’d swim around the oceans with his beloved, show him the wonders of the depths and the beauty and power of the seas. They’ll fill the waters with their children and Eren will stay by his side forever.

He sang again, indulging Eren with his wish. The brunet was deeply enchanted of the merman’s voice, by its richness and dark tone yet they held such gentleness and love as he confessed his love over and over again. Despite the foreign language spoken from the merman’s lips, Eren had understood his words since Levi had enchanted him a spell to infuse every form of language to the child’s mind to which Eren was happy to make use of in his greetings and sometimes, admissions of his affections to the merman.

“Levi, you’ll stay with me forever right? You won’t leave me alone here, right?” It wasn’t so surprising, the sudden solemn inquisition of the youthful voice. The heart remembered its scars and despite his mind having no traces of his memories, his heart ached of the loss and the grief of his family leaving Eren weeping for love and attention, of familiarity and security. The fear to be left again grappled his soft and gentle heart and Levi wouldn’t have that, and so he vowed with absolute finality, “My love, my jewel, my Eren, I’m not going anywhere. I’ve been waiting for you all my life, and now that I have you, I have no intention of letting you go. Rest assured I’m here to stay for the rest of eternity.”

The young child sobbed, hands clutched to broad shoulders with a powerful clasp. His oceanic eyes gleamed with tears of happiness brought upon by the merman’s irrevocable declaration. A kiss on the lips sent him reeling, the affection and contact bringing him reassurance that the merman’s love and promise to him was never a lie.

Levi stayed in his human form like the rest of the nights before, embracing his lover in the shroud of moonlight. The hearth of the firewood dancing in their flesh as both heartbeats thrummed as one.

 

* * *

 

The shifting waves were high up, stretching to the skies. The moon was full and aglow with its serene silver light. Eren stood amongst the shore and sea, the light of the moon surrounding him like a halo. He took in the pale hand offered to him, the red crimson dripping on its pale surface. His tongue laved the tainting liquid with no repulsion and trepidation amongst the taste of iron and salt that flourished his mouth. A lyrical chant filled the breezy night, dancing along the roll of the ocean, lulling the child into a trance like state as his senses doused into the voice of the merman’s.

A blood shared is a bond shared. Levi had told him. For him to be enchained forever with the merman, Eren has to consume Levi’s blood and offer his to establish a profound bond. Levi’s blood will change him once the ritual is over and he will become Levi’s mate.

Water sloshed to his hips, his body bare to the merman as the other moved closer, wet pale skin against golden. Eren’s breath hitched when he met sight of silver, the dark of the ocean casting a blue shadow unto the glowing silver orbs. Eren lost himself to it, like the ocean he was reeled into its embrace and Eren welcomed its warming look with a kiss.

Fingers ghosted over his back, its sharp nails careful, so not to cut through the surface and Eren tilted his head back, lips slightly agape as soft gasps escaped him with anticipation. Canines poised in for a bite, and the merman dug them deep into the child’s shoulder. A pained cry left Eren’s lips, and the merman drank in, fast and sure, tongue pouring out its saliva to heal the wound immediately.

The skin of his shoulder itched with liquid fire and heat bloomed through him. The child called out Levi’s name, voice airy and out of breathe and the merman brought him closer to the deep waters, submerging him. Slits formed unto the smooth column of his neck and Eren found out that he could breathe just as normal underwater. His feet formed together, shifting and Eren, in his new form of eyesight, saw clearly how they transformed to a tail of bright blue, green and gold.

It was now complete.

Giving it a test, Eren moved the large appendage with a strong strength. The action propelled him closer to the ocean surface, and the young child let out a giggle in its clumsy attempt to copy the merman’s wonderful movements. With a hand offered to him, the older male guided him, teaching him the basics of swimming and even giving the child a playful twirl in the water. Eren felt like he was stuck in a wondrous dream, never to end and wouldn’t have it in any other way.

Surging over the merman, he placed a kiss on pale lips, feeling it unfold sharp teeth as a smile took its place. Hands, rough and possessive, slithered around him and Eren reeled into the embrace, the bond pouring out the other’s desire, lust and love directed to him that he found himself intoxicated with the emotions vibrating through their connection.

“You’re so beautiful Eren.” Levi purred, voice carried over by the water and the young mermaid’s heart paced, pride and contentment blooming across his chest with the praise.

“You are too, Levi.” He replied and the merman sought his lips, kissing him fervently and dripping liquid pheromones unto that eager mouth to coax a pseudoheat. Eren moaned against him, and the merman moved them closer to the shore, laying his mate on the sand as he ravished sun-kissed skin with kisses, sucks and bites. The child, despite the foreign arousal, accepted the pleasure brought about by the merman’s hungry mouth. Hands all demanding of his being, scraped and kneaded his flesh with reverence and awe. Such only showed the merman’s desperation to him and the young child felt high at the strong affection shown by his mate.

A moan reverberated through him when Levi swallowed his nipple, both tongue and teeth making him curl and plead for more. His loins hurt and something lower to his stomach ached. He needed something, he needed his mate.

“Please Levi.” He begged, unsure of what it was he was asking but he trusted that his mate would be able to comprehend his body more than he could.

A finger lingered along his abdomen and then with sure motion it slipped inside him. Eren doesn’t know how, but the appendage was making such hypnotic movements, enticing sweet euphoria to the young mermaid. Squeals of delight were elicited from Eren’s lips and the merman continued, adding another inside the wet entrance hidden underneath the slit. In mermaid form Eren would manifest female reproductive organs but if he shifts to his human form, his exterior would be of a male, but the womb and eggs would still be inherent internally.

Bending himself down, his mouth feasted over the sweet slick of his mate’s cavern, tongue working with his fingers, dragging the nails slightly over the quivering flesh. Eren mewled upon the delicious friction worked by his mate, his spine curling as sharp yet desirable stabs of pleasure surged through his body. He took hold of those strong shoulders, hips arching towards the ravenous mouth that seemed to be eager in devouring his cavern.

“Eren, Love, do you trust me?” Levi’s voice rang loud and clear, and Eren looked over to see a large organ protruding on the man’s crotch. The length was purple with a darker shade to its tip that was leaking with pearlescent liquid. The organ though menacing, made the mermaid shiver in excitement. Something inside told him that he needed to be filled by it, to be ravaged and marked by its seed. And just the thought of Levi staining him inside, making him his and only his gave him enough motivation to entrust his mate. Making a few nods, the child urged the merman by a sure thrust of his tail.

The merman, having to decipher the message, positioned his cock into the slit, pushing in slowly to avoid bringing unnecessary pain to his mate. A deep groan echoed through his throat upon having to fill the other up to the brim. Making a soft and shallow thrust, he moved his hips against the younger child, earning himself a pleased moan that urged him to continue.

Eren never thought it could be more amazing. The fingers gave him already such bliss but with older male’s member, it was so much euphoria that it made him high and drunk with stimulation. It was rubbing over his insides, its hardness forming such languid friction that seemed to ignite something in him, coalescing and growing until it was ready to be released.

With pace increasing, the merman strengthened his thrusts, plunging deeper and fuller into the mermaid. His lips surged with fervent avidity as he marked once again the painted canvas of his beloved mate. That tightly, wet cavern was squeezing him so greedily, urging his orgasm to unfold so quickly and the merman wanting to bring his mate to completion, shifted his strident thrusts to a relentless conquest, rolling his hips to hit the right spot to make his mate reach his climax.

His sight burned with white flashes underneath the onslaught of his mate, his mouth screaming and moaning a debauched song as tension grew thicker and heavier inside his core. He was close, his entire being tightening as the hot coals of pleasure burned hotter and bigger until they explode like tiny supernovas inside him. He screamed the merman’s name, calling and reaching, clutching to him for anchor because Eren felt like he was flying into the skies, soaring higher to the celestial stars.

Levi reached his peak upon knowing that his mate had achieved his. He plunged himself deep into Eren’s fragile womb, spilling his rich seed into that seeking cavern and locking them together with an inflated knot. Though Eren wouldn’t be able to bear fruit of their mating since he was not of age where his heat could provide a fertile womb for his children, it did not matter to the merman. Eren was his now for all eternity as his beloved, his mate and the bearer of his children, and such was enough to suffice the lashing longing and pain of loneliness for his Eren.

Giving a soft peck on reddened cheeks, the merman nuzzled on that fragile chest heaving for air. Eren’s scent was so sweet and delectable that the older man couldn’t help but to inhale for a taste over jugular of his neck. He received a soft whimper from the child and he stretched up, taking in such lovely sight of his lover. Eren looked utterly breathless with his soft lush lips that throbbed red with their kisses, his eyes were like glittering jewels aflame with love and awe directed towards him. His body was an art of love bites and suck marks, the impressions of his nails cultivating such a lovely pink color unto the golden flesh.

His mate was gazing at him, with adoration and with so much love, that the young mermaid blushed. Strong arms wrapped around him with a reverent embrace, and Eren returned with it wholeheartedly, smiling over the broad shoulder. Dazed with post-coital afterglow, Eren almost did not catch the merman’s voice telling him, “Eren, mark me. Brand me as yours love,” The man exposed his neck further, and the mermaid, impulsed by his instincts to claim his mate, bit into the porcelain flesh near the juncture of his shoulder and neck. Levi let a groan, and Eren shivered, feeling the older man’s cock grow to hardness once again.

Emboldened by the reaction, Eren made a meek thrust to which coaxed a moan from his lips. Levi smelled so good, dominant and amorous, and Eren rolled his hips, feeling the member reach its full hardness and it made him ache again with need and lust. It was addicting, this ritual that seemed to connect them closer and entwine them together.

Taking notice of this, the merman wrapped his hands around the child’s waist and back. He utilized the strength of his strong tail, standing almost upright as the large appendage bended slightly to support his upper body. Levi pressed Eren flush to his chest and started to pistol his hips against the child’s, driving his cock into that hot and slick entrance. He felt Eren shudder against him, his little hands clinging to him with a vice-like grip, his lithe body moving against him, meeting his thrusts.

Over and over, he claimed the child once again, spurring their orgasms with each drive of his hips. Leaning over the tanned shoulder, he bit his mate to reciprocate the mark. It would serve as a physical proof of their bond, their unification and love.  Eren bended in the older man’s arms, neck exposed and chest heaving with an arch as he reached another climax brought about the intense shock of pleasure when the merman bit him. Gasping for air, his body convulsed against the muscled torso of his mate, praises and appreciations singing from his quivering lips as the other stilled and spilled his seed inside of him.

Levi’s cock pulsed and twitched against his clenching walls, the warmth of his essence filling him. They were interconnected once again by the swelling knot, and Eren didn’t want to let go and be separated from his mate. Eren wanted to stay with Levi forever, just thought of being alone and left by the merman was dreadful enough.

Eren decided, from here on he’ll do anything just to keep Levi his and only his.

 

* * *

 

_Three years passed..._

Eren swam through the quiet waters near a private dock. The sky up above had shifted to soft purple with hints of red and pink, the dark edges of the night slowly sweeping along the light as the night gradually took its place.  He was waiting for a friend of his to reach the dock and meet him. Hiding in the waters, Eren swayed his fins in impatience. Levi was waiting for him to come home and he doesn’t want to worry his mate for being late, especially that he had traveled near shore without him. The merman had warned him about being seen and caught by humans, and the possible horrors that they would do to a creature like him, but Eren missed his friend, and besides the humans that seem to visit the shores were more likely to be the owners of the residential mansion that was built near the sea. So he found it no harm to journey along its isolated shores.

Finishing a meal that he hunted along the way, he peered to see two children walking along to the edge of the dock, with a much older man—Eren guessed him to be their father—trailing after them. The children were two girls, the oldest had ties her mahogany brown locks in pigtails, her eyes a light shade of green from what his sharp eyes could perceive from such a far distance. The other was much younger, probably four and her hair as dark like man’s and so are her eyes. The youngest was carrying with her a lotus lantern, already lit and glowing softly with the ember of the candle.

Eren felt a pinch in his heart to which he decided to ignore.

The mermaids ears perked upon hearing a croaked bark. He almost jumped out of the water to see his friend, a golden dog to which was called Armin, padding closer to the children. The child with pigtails patted his head, and helped the youngest lay the lantern into the sea. Eren caught a whisper of a sob from the youngest and a sniff from the other, and he concluded that someone they love must’ve died at sea, thus performing this ritual of remembrance.

The father, kneeled on his right knee to hug his children, a saddened look in his eyes and he said something to lift his children’s spirits up. He lifted the youngest when they left, and Armin stayed, sitting on the wooden dock, eyes on the sea.

When Eren deemed the area safe of humans, he crossed through the waves, stopping by the edge of the dock. He heard a whine when he emerged from halfway from the ocean, and received a lick from the dog as he leaned to brush the golden fur of its head.

“Hey, Armin. How are you, old friend? It’s been another year since we’ve met again.”

Eren said wistfully, voice low and quite enough for just the dog to hear. He’d met Armin a year after he turned to a mermaid. He was wandering about in the local beach of that particular area, when he noticed the golden dog casting a mournful look in the sea. When he caught sight of Eren, he suddenly howled and barked excitedly into the waters, jumping and swimming towards him as fast as his weakened legs could handle. That day Eren earned a friend from the shores, and he kept it secret to his mate that he rarely visited the private dock as he knew that his mate would be against it, even more now that he was of child.

“Here boy, another sweet treat for you.” He offered, and Armin ate it with no hesitance and uncertainty. He had been feeding the dog some of his concoction, one that would offer strength and good health for the aged dog. Eren knew that he was past his life expectancy and yet the poor thing struggled to survive.

“I can’t stay too long today, my husband is waiting for me to come home. Tomorrow, we’ll leave for another country to journey the tropical waters of the Caribbean sea. I’m so excited!!” Eren chirped, rubbing the dog’s ears. Indeed, exploring and discovering the hidden wonders of the sea with his beloved mate made Eren all giddy and ecstatic. All year round they travel the world, surging through the vast waters and sea. They return here on Maria, his husband’s birthplace occasionally, but he had a feeling that his husband was planning to have him give birth to their child here, where the waters are more peaceful and warm, yet rich in life and freedom.

The thought of having a child scared him a little, but Eren has his husband to support him and protect him. His maternal instincts were already kicking in early, often making him so clingy and affectionate to his mate, though he knew Levi didn’t mind, all the more his husband seemed to appreciate his loving gestures. Even more he was more hormonal, leading to so many heated nights, and sometimes mornings.

“I’ll miss you old buddy, but I’ll visit you again as soon as I could, so stay strong ok?”

Armin made a bark, and licked his right cheek, and Eren interpreted it as an affirmation. He gave the dog one last pat on the head before he dove back to the ocean, rushing back to his mate.

Upon the journey home, he heard Levi’s voice inquire, “Oi brat, where have been?” He twirled to see the other swimming towards him and Eren lurched to his mate, kissing those pale lips in greeting. The older male pecked both golden cheeks, and Eren giggled when he nuzzled into his shoulder, giving a nip on the claiming mark.

“Exploring.” He offered and Levi gave him a reprimanding stare as they both swam back home. “Brat, I told you not to stray too far away from home, something could happen to both of you.” Levi chastised, and wrapped an overprotective arm around Eren’s growing belly.

“Sorry for making you worry. But I was careful enough, so no worries. I would never let anyone hurt our child.” The mermaid vowed. He received a smile from the other, and Eren embraced his mate, pouring his heart and soul at the affectionate gesture. A calloused hand took of his, bestowing a kiss on the palm and pulsing wrist. Turquoise met silver, and Eren cupped the jaw of his mate to brush their noses affectionately.

“I love you.” He whispered. Heart and soul, Eren was complete, fulfilled and loved for eternity.

The man sought his lips in a passionate kiss and declared with all truth and emotion.

“I love you too, my Eren.”

 

* * *

 

**Author's Note:**

> Comments, constructive criticisms are appreciated!! Thanks for reading!!!


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